In this article you are going to learn how to install Postfix on your already running Debian 5.0.
I am going to assume you have it networked and have a domain registered that you want to use. At the end of this article you should have a working mail server, ready for use:
apt-get install postfix
The file for confugure is /etc/postfix/main.cf.
To set your Postfix installation up for your domain you will want to open that file for editing like so:
The above command opens main.cf in the Nano editor. What you need to look for is this section: